Free-standing electrochemical electrode based on Ni(OH)₂/3D graphene foam for nonenzymatic glucose detection

Three-dimensional graphene foam (3DGF) is a superior sensing material because of its high conductivity, large specific surface area and wide electrochemical potential windows. In this work, hexagonal Ni(OH)₂ nanosheets are deposited on the surface of chemical vapor deposition-grown 3DGF through a facial hydrothermal process without any auxiliary reagents. The morphology and structure of the composite are characterized by scanning electron microscopy (SEM), transmission electron microscope (TEM), Raman spectroscopy, and X-ray diffraction (XRD). Based on the Ni(OH)₂/3DGF composite, a free-standing electrochemical electrode is fabricated. Being employed as a nonenzymatic glucose detection electrochemical electrode, it exhibits a high sensitivity (∼2.65 mA mM^-1 cm^-2), low detection limit (0.34 μM) and excellent selectivity with a linear response from 1 μM to 1.17 mM. The excellent sensing properties of the Ni(OH)₂/3DGF electrode may be attributed to the synergistic effect of the high electrocatalytic activity of Ni(OH)₂ nanosheets and the high conductivity and large surface area of 3DGF.